Metaplastic (infarcted) Warthin's tumour of the parotid gland: a possible consequence of fine needle aspiration biopsy

The differential diagnosis of lymphoepithelial lesion of the salivary gland

The differential diagnosis of salivary gland lesions with epithelial components and lymphoid stroma is often challenging. Salivary gland carcinoma with tumor-associated lymphoid proliferation, tumors composed of both epithelial and lymphoid components, lymphoid neoplasms in the salivary gland, and inflammatory lesions are all included in this category. It encompasses inflammatory lesions and neoplastic lesions. With the exception of Warthin tumors, these lesions are rare, making them more difficult to diagnose. Carcinoma showing thymus-like elements has recently been reported in the salivary gland. Similar to thymic carcinoma, tumor cells are positive for CD5 and are accompanied by T lymphocytes.

KRAS codon 12 mutations characterize a subset of de novo proliferating "metaplastic" Warthin tumors

Warthin tumor (WT; synonym: cystadenolymphoma) represents one of the most frequent salivary gland tumors with a frequency equaling or even outnumbering that of pleomorphic adenomas in some series. Histologically, the tumor displays tall columnar oncocytic cells, arranged into two cell-thick layers lining variably cystic glands within an organoid lymphoid stroma. Tumors with exuberant squamous metaplasia in response to FNA-induced or other types of tissue injury/infarction have been referred to as "metaplastic WTs." However, the same terminology was used for tumors with variable mucinous cell and solid or stratified epidermoid proliferations (occasionally mimicking mucoepidermoid carcinoma), although the "metaplasia concept" has never been proven for the latter. We herein investigated 22 WTs showing prominent mucoepidermoid-like or solid oncocytoma-like proliferations without prior FNA or histological evidence of infarction/ trauma using the TruSight Tumor 15 gene panel and KRAS pyrosequencing. As a control, we tested 11 conventional WTs. No statistically significant differences were observed between the two subcohorts regarding patient's age and tumor size. Six of 22 (27%) proliferating/ metaplastic WTs revealed oncogenic KRAS mutations clustering at codon 12 (exon 2), while all conventional tumors lacked these mutations. Our findings are in line with a neoplastic nature of the epidermoid/ mucoepidermoid proliferations in non-injured "metaplastic" Warthin tumors. We propose the descriptive term "de novo proliferating Warthin tumor" for this variant to distinguish it from infarcted/inflamed genuine metaplastic Warthin tumor.

Warthin-Like Mucoepidermoid Carcinoma: A Morphological Spectrum - A Report of 3 Cases with Histological and Cytological Findings and Review of the Literature

BACKGROUND

Mucoepidermoid carcinoma (MEC) showing Warthin's tumor (WT)-like features is a low-grade malignancy which should be differentiated from WT. Morphological features may be distinctly different in each case, causing diagnostic difficulties.

CASE PRESENTATION

Three cases were presented and discussed with their morphologies. All cases that presented with a mass in the parotid gland went to parotidectomy, and all had preoperative fine-needle aspirations (FNAs). Case 1 was a 16-year-old female; FNA was suggestive of WT and initially interpreted as WT histologically. Case 2 was a 27-year-old male; FNA was interpreted as noninformative due to the presence of cyst fluid only. Case 3 was a 53-year-old male and cytologically was found to be suspicious for MEC which contained squamous and goblet cells on a mucoid background. On histopathological examination, case 2 and case 3 were morphologically consistent with low-grade MEC with WT-like features. Prominent lymphoid stroma and the cystic pattern were the characters of these tumors. Case 1 had the classical WT appearance with some mucinous and squamous metaplasia which could only be interpreted as MEC after the detection of MAML2 rearrangement by FISH. The other 2 showed either focal or relatively diffuse usual low-grade MEC findings, and case 3 was also confirmed by MAML2 rearrangement.

CONCLUSION

Cytological and histopathological features revealed a spectrum. Differentiating WT-like MECs from ordinary WTs may be challenging. On the one end of the spectrum, they may look very much like WT, and on the other end, even though usual MEC features are present, still, WT-like appearance may pose diagnostic difficulty. Showing MAML2 rearrangement in these cases is very helpful. The presence of mucinous and squamous cells in an otherwise WT-like looking tumor should be alarming for MEC, and if possible, each case should be analyzed for MAML2 rearrangement.

Current Trends and Controversies in the Management of Warthin Tumor of the Parotid Gland

Purpose: To review the current options in the management of Warthin tumors (WTs) and to propose a working management protocol. Methods: A systematic literature search was conducted using PubMed and ScienceDirect database. A total of 141 publications were selected and have been included in this review. Publications were selected based on relevance, scientific evidence, and actuality. Results: The importance of parotid WTs is increasing due to its rising incidence in many countries, becoming the most frequently encountered benign parotid tumor in certain parts of the world. In the past, all WTs were treated with surgery, but because of their slow growth rate, often minimal clinical symptoms, and the advanced age of many patients, active observation has gradually become more widely used. In order to decide on active surveillance, the diagnosis of WT must be reliable, and clinical, imaging, and cytological data should be concordant. There are four clear indications for upfront surgery: uncertain diagnosis; cosmetic problems; clinical complaints, such as pain, ulceration, or recurrent infection; and the patient’s wish to have the tumor removed. In the remaining cases, surgery can be elective. Active surveillance is often suggested as the first approach, with surgery being considered if the tumor progresses and/or causes clinical complaints. The extent of surgery is another controversial topic, and the current trend is to minimize the resection using partial parotidectomies and extracapsular dissections when possible. Recently, non-surgical options such as microwave ablation, radiofrequency ablation, and ultrasound-guided ethanol sclerotherapy have been proposed for selected cases. Conclusions: The management of WT is gradually shifting from superficial or total parotidectomy to more conservative approaches, with more limited resections, and to active surveillance in an increasing number of patients. Additionally, non-surgical treatments are emerging, but their role needs to be defined in future studies.

Conventional, diffusion, and dynamic contrast-enhanced MRI findings for differentiating metaplastic Warthin's tumor of the parotid gland

The purpose of this study was to explore conventional, diffusion, and dynamic contrast-enhanced MRI (DCE-MRI) characteristics for differentiating metaplastic Warthin's tumor (MWT) from other tumor types of the parotid gland, including non-metaplastic Warthin's tumor (non-MWT), pleomorphic adenoma (PA), and malignant tumor (MT). A total of 178 patients with histologically proven tumors of the parotid gland, including 21 MWTs, 49 non-MWTs, 66 PAs, and 42 MTs, were enrolled in the study. Conventional MRI was performed in all patients. One hundred and fifty patients had preoperative diffusion-weighted MR imaging (DWI), and 62 patients had preoperative DCE-MRI. The differences in the conventional, DCE-MRI, and DWI records between MWTs and the other three tumor types were statistically evaluated. Compared with non-MWTs and PAs, there was a statistically significant difference in circumscription (p < 0.01). The ill-defined circumscription was more common in MWTs than non-MWTs and PAs. Compared with PAs, there was a statistically significant difference in morphology (p < 0.05). The lobulated morphology was more common in PAs than MWTs. Compared with PAs and MTs, there was a statistically significant difference in the T2 signal of the solid component (p < 0.01). The T2 moderate intensity of solid components was more common in MWTs than PAs and MTs. The solid components of PAs mostly showed hyperintense on T2-weighted imaging. Cyst/necrosis was more common in MWTs than PAs and MTs. Hyperintense of cyst/necrosis was more common in MWTs and non-MWTs. With respect to contrast enhancement, 52.4% MWTs exhibited moderate or marked enhancement, and most non-MWTs (81.6%) exhibited mild enhancement. Most PAs (84.8%) exhibited marked enhancement. The mean ADC value of MWTs (0.94 × 10-3 ± 0.11 mm2/s) was significantly lower than that of the PAs (1.60 × 10-3 ± 0.17 mm2/s) (p < 0.001). On DCE-MRI, six of eight MWTs demonstrated TIC of type B. Although MWT is rare, conventional MRI characteristics, DWI and DCE-MRI can provide useful information for differentiating MWT from other parotid mass.

Ulcerative Warthin Tumor: A Case Report and Review of the Literature

Warthin tumor with ulceration of the surrounding skin is extremely rare, making it difficult to differentiate from parotid cancer in the clinical setting. We report a 65-year-old man with a Warthin tumor in the right parotid gland that had ulceration of the overlying skin. The patient presented with right upper neck mass 2 years ago. Ultrasound and fine needle aspiration were done, and Warthin tumor was suspected. One year later, the mass was enlarged with ulceration of the skin. Superficial parotidectomy with fusiform excision of the skin was performed, and histopathological diagnosis revealed a Warthin tumor with inflammatory change. We proposed that this unique manifestation may have been induced by fine needle aspiration, enlargement of the tumor, and ischemic changes secondary to pulmonary arteriovenous malformations.

MAML2 rearrangement as a useful diagnostic marker discriminating between Warthin tumour and Warthin-like mucoepidermoid carcinoma

Warthin tumour is the second most common benign neoplasm of salivary glands. Despite its relatively characteristic histology, it may sometimes mimic other lesions. Here, we report two female non-smoker patients diagnosed with low-grade mucoepidermoid carcinoma with oncocytic epithelium and prominent lymphoid (Warthin-like) stroma and with molecularly confirmed MAML2 rearrangement. In addition, we screened a consecutive series of 114 Warthin tumour cases by means of MAML2 break apart fluorescence in situ hybridization to assess its value in differential diagnosis. MAML2 rearrangement was detected in both mucoepidermoid carcinoma cases, while all Warthin tumours were negative. Taking into account the literature data, Warthin-like mucoepidermoid carcinomas are more frequently observed in women, while a slight male predominance and smoking history are typical for Warthin tumour. In addition, the patients with Warthin-like mucoepidermoid carcinoma were significantly younger than those with Warthin tumour. To conclude, Warthin-like mucoepidermoid carcinoma may usually be suspected based on histology, while the diagnosis can be confirmed by means of molecular assays such as FISH. The investigation of MAML2 status is particularly advised when Warthin tumour is considered in a young, non-smoking, female patient.

The significance of mucinous metaplasia in Warthin tumor: a frequent occurrence and potential pitfall

Mucinous metaplasia in Warthin tumor (WT) is a recognized phenomenon. Nevertheless, its presence can create a diagnostic challenge in the distinction from the newly proposed variant of mucoepidermoid carcinoma (MEC), Warthin-like MEC. In this study, we evaluated the significance and diagnostic relevance of mucinous metaplasia in WTs. A total of 30 WTs diagnosed based on resection specimens formed the basis of this retrospective study. Mucicarmine staining was performed to identify mucinous metaplasia, and fluorescence in situ hybridization (FISH) analysis was used to detect MAML2 gene rearrangement. After review, one MAML2 rearranged case was reclassified as Warthin-like MEC as the classic bilayered epithelium in WT was not identified. The diagnosis of WT was confirmed in the remaining 29 cases. Mucinous metaplasia was encountered in 24 WTs (83%), with 14% (4/29) having an abundant amount. We found that mucinous metaplasia correlated with tumor size (p < 0.05). Age and sex distribution were similar in WT cases with or without mucinous metaplasia. In addition, neither the presence of squamous metaplasia nor the time interval between fine-needle aspiration and surgery was related to mucinous metaplasia (p > 0.05). The MAML2 FISH analyses performed in 18 WTs with variable amounts of mucinous metaplasia were negative for rearrangement. In conclusion, mucinous metaplasia is fairly common in WTs and shows a significant correlation with tumor size. Therefore, caution should be taken to avoid overinterpretation of WT with mucinous metaplasia as MEC in cases showing the classic bilayered oncocytic lining epithelium.

The Role of Molecular Testing in the Differential Diagnosis of Salivary Gland Carcinomas

Salivary gland neoplasms are a morphologically heterogenous group of lesions that are often diagnostically challenging. In recent years, considerable progress in salivary gland taxonomy has been reached by the discovery of tumor type-specific fusion oncogenes generated by chromosome translocations. This review describes the clinicopathologic features of a selected group of salivary gland carcinomas with a focus on their distinctive genomic characteristics. Mammary analog secretory carcinoma is a recently described entity characterized by a t(12;15)(p13;q25) translocation resulting in an ETV6-NTRK3 fusion. Hyalinizing clear cell carcinoma is a low-grade tumor with infrequent nodal and distant metastasis, recently shown to harbor an EWSR1-ATF1 gene fusion. The CRTC1-MAML2 fusion gene resulting from a t(11;19)(q21;p13) translocation, is now known to be a feature of both low-grade and high-grade mucoepidermoid carcinomas associated with improved survival. A t(6;9)(q22-23;p23-34) translocation resulting in a MYB-NFIB gene fusion has been identified in the majority of adenoid cystic carcinomas. Polymorphous (low-grade) adenocarcinoma and cribriform adenocarcinoma of (minor) salivary gland origin are related entities with partly differing clinicopathologic and genomic profiles; they are the subject of an ongoing taxonomic debate. Polymorphous (low-grade) adenocarcinomas are characterized by hot spot point E710D mutations in the PRKD1 gene, whereas cribriform adenocarcinoma of (minor) salivary glands origin are characterized by translocations involving the PRKD1-3 genes. Salivary duct carcinoma (SDC) is a high-grade adenocarcinoma with morphologic and molecular features akin to invasive ductal carcinoma of the breast, including HER2 gene amplification, mutations of TP53, PIK3CA, and HRAS and loss or mutation of PTEN. Notably, a recurrent NCOA4-RET fusion has also been found in SDC. A subset of SDC with apocrine morphology is associated with overexpression of androgen receptors. As these genetic aberrations are recurrent they serve as powerful diagnostic tools in salivary gland tumor diagnosis, and therefore also in refinement of salivary gland cancer classification. Moreover, they are promising as prognostic biomarkers and targets of therapy.

Spontaneously infarcted parotid tumours: MRI findings

OBJECTIVES

To report MRI findings of spontaneous infarction in parotid tumours.

METHODS

14 patients (13 male, 1 female; mean age 73 years) with spontaneously infarcted parotid tumours were reviewed retrospectively. MR images were assessed for the location, the presence of synchronous parotid masses, margin characteristics, signal intensity on T ₁ and T ₂ weighted images, and internal architecture according to the distribution of T ₂ signal hyperintensity.

RESULTS

12 tumours were located in the parotid tail and 2 in the superficial lobe. Synchronous parotid masses were seen in four tumours, three of which were located in the ipsilateral parotid tail and one in the contralateral parotid tail. Seven tumours had well-defined margins and seven had ill-defined margins. The signal intensities on T ₁ weighted images were a mixture of high and intermediate in all cases; in 11 tumours, hyperintense areas were dominant. On T ₂ weighted images, all tumours also showed a mixture of high and intermediate signal intensities. Internal architectures on T ₂ weighted images were mosaic hyperintensity in three tumours, central hyperintensity in five, and multiseparated hyperintensity in six.

CONCLUSIONS

Spontaneously infarcted parotid tumours were mostly located in the parotid tail and showed mixed signal intensities with predominant hyperintensity on T ₁ weighted images. Half of the tumours had ill-defined margins, and the internal architectures varied.

Infarcted Warthin tumor with mucoepidermoid carcinoma-like metaplasia: a case report and review of the literature

Background

Warthin tumor is a common, benign, painless salivary gland neoplasm. Rarely, Warthin tumors show large areas of squamous metaplasia; such Warthin tumors are called metaplastic or infarcted Warthin tumors because they are occasionally accompanied with tumor necrosis. The histological distinction between mucoepidermoid carcinomas and the metaplastic portions of Warthin tumors can be challenging; without a genetic study, mucoepidermoid carcinomas can be misdiagnosed as metaplastic Warthin tumors. We report a case of infarcted Warthin tumor partly showing mucoepidermoid carcinoma-like epithelial metaplasia. Only two cases of infarcted Warthin tumor similar to our case have been reported.

Case presentation

A 69-year-old Japanese man presented with a right parotid tumor. He had noticed the swelling on his right buccal region 1 year previously; the lesion had rapidly enlarged, with associated pain, 1 month previously. A radiological examination revealed a mass in the tail of the right parotid gland. Superficial parotidectomy was performed. On histological examination, the mass showed typical focal features of Warthin tumor; other areas showed coagulation necrosis of the tumor. These areas were surrounded by non-oncocytic epithelium comprising squamous and mucinous epithelial cells. Although cellular atypia of the non-oncocytic epithelium was not observed, a mixture of squamous and mucinous cells and lack of abundant lymphoid tissue mimicked low-grade mucoepidermoid carcinoma. Based on the results of fluorescence in situ hybridization, MAML2 gene rearrangement was not present in the typical portions of Warthin tumor and the mucoepidermoid carcinoma-like lesion. Therefore, a metaplastic or infarcted Warthin tumor was diagnosed. Our patient was disease-free 8 months after surgery.

Conclusions

Clinicians need to know that pain is a clinical symptom of infarcted/metaplastic Warthin tumor. Pathologists should be aware that a metaplastic Warthin tumor can mimic a low-grade mucoepidermoid carcinoma. Our case showed a mucoepidermoid carcinoma-like lesion that was confined near the area of tumor necrosis, and neither cytological atypia nor apparent invasive growth was present. These findings appeared to be histological clues of a metaplastic Warthin tumor rather than a mucoepidermoid carcinoma. Careful clinicopathological evaluation as well as genetic studies are needed to clarify the distinction between mucoepidermoid carcinoma and metaplastic portions of Warthin tumors.

Ultrasound-guided fine-needle capillary cytology of parotid gland masses coupled with a rapid-on-site evaluation improves results

OBJECTIVE OF THE STUDY

To test whether a direct-on-site microscopic examination of fresh, unstained puncture slides by the radiologist decreases the rate of false-negative cases on ultrasound-guided fine-needle cytology of parotid gland masses.

PATIENTS

Thirty parotid gland masses from 28 patients were punctured under ultrasound guidance. The same group was used as its control group.

METHODS

After one or two passes, the material was spread on slides and air-dried (control group, without microscopic examination). For the study group, it was thus analyzed unstained under the microscope. A sample was considered adequate if at least six clusters of parotid cells were found per slide on at least two slides. For the study group, new punctures were obtained and slides prepared until this condition was fulfilled.

RESULTS

Of the 30 evaluated masses, 100% benefited from a cytological diagnosis after microscopy. Twenty-four were adequate in the control group, while 30 were adequate in the study group. The maximum number of punctures to obtain an adequate sample was six. On-site direct microscopy significantly increased the number of adequate specimens by 20% (P=0.03, CI [1.63-20%]).

CONCLUSION

Direct and systematic examination of slides by a radiologist avoided the risk of false-negative results caused by having insufficient sample material.

Warthins tumor: Cyto histological spectrum with emphasis on diagnostic difficulties

Warthins tumour is characterized by the presence of epithelial proliferation in a lymphoid stroma. It has been categorized as Sieferts types: 1-4, depending on the proportions of the 2 components. Although FNA is fairly accurate in establishing the diagnosis, the cytologic diagnosis of this tumor has potential sources of error. This retrospective study was conducted in the Department of Pathology and Lab Medicine, of a tertiary care hospital. Cytology and surgical pathology records of past 15 years were screened. A total of 1200 FNAC cases of salivary gland lesions in the past 15 years were retrieved. 36 cases with presumptive cytodiagnosis of WT were identified and histopathological correlation was done. Histopathological correlation could be done in 24 cases. 19 out of 24 cases, were confirmed as WT. The 5 cases with discordance were analyzed for potential diagnostic pitfalls. The most common discordance was in the category of papillary proliferation with minimal lymphoid infiltrate. One case proved as oncocytoma and the other was papillary oncocyticcystadenoma. The other major pitfalls, were the interpretation of atypical squamoid cells. Their presence in a lymphoid background needs consideration of cytologic diagnosis of WT, mucoepidermoid carcinoma and metastatic squamous carcinoma. FNA showed an accuracy of 79% for WT. Cytological misinterpretation can thus occur in presence of morphology other than classical Siefert type1. An awareness of these potential pitfalls should push the need for avoiding single cytologic interpretation.

Inflammation following invasive procedures for Warthin's tumour: A retrospective case series

OBJECTIVE

To determine the risk of inflammation associated with fine-needle aspiration during evaluation of Warthin's tumour.

DESIGN

Retrospective case series.

SETTING

Tertiary medical centre.

PARTICIPANTS

All patients who underwent fine-needle aspiration followed by parotidectomy between 1992 and 2009 for the diagnosis/evaluation of a parotid gland tumour.

MAIN OUTCOME MEASURE

Rate of fine-needle-aspiration-related parotitis in patients with Warthin's tumour or other parotid pathologies.

RESULTS

A total of 593 parotidectomies were performed in 553 patients during the study period, 96 (16.2%) for Warthin's tumour (study group) and 497 for other parotid-related pathologies (control group). Parotid gland inflammation following fine-needle aspiration was observed in 16 cases in the study group (16.7%) and eight (1.6%) in the control group (P<.001). On multivariate regression analysis, parotitis following fine-needle aspiration was more common in patients with Warthin's tumour than other parotid-related pathologies even after adjustment for possible confounders (P<.007). Signs of inflammation were noted during surgery in six cases in the study group (6.3%) and none in the control group (P<.001); respective rates of postoperative inflammation (wound infection) were 1.04% and 3.3% (P=NS). Management of parotitis consisted of hospitalisation and systemic antibiotic therapy.

CONCLUSIONS

Warthin's tumour is associated with a tenfold higher risk of inflammation compared to other parotid tumours following invasive procedures. Clinicians should be alert to this complication in order to initiate proper treatment and patients must be properly counselled.

The accuracy of fine-needle aspiration cytology for diagnosis of parotid gland masses: a clinicopathological study of 114 patients

Objective

Fine-needle aspiration cytology is a valuable method for preoperative assessment of head and neck tumors. However, its accuracy in detection of salivary gland masses is controversial compared with other methods. The aim of this work was to evaluate the effectiveness and accuracy of fine-needle aspiration cytology (FNAC) in the diagnosis of parotid gland masses.

Material and Methods

Over a 10-year period, 126 parotid gland masses were resected. Retrospective chart reviews of 114 patients were performed. The results of FNAC and final histological diagnosis were compared and the accuracy of FNAC was determined.

Results

Final histological evaluation revealed 11 malignant tumors and 103 benign lesions. Pleomorphic adenoma was the most common neoplasm (63%), followed by Warthin’s tumor (17.5%). The sensitivity of FNAC in detecting malignant tumors was 73% and the specificity was 97%. Positive predictive value (PPV) was 73% and negative predictive value (NPV) was 97%. The overall accuracy of FNAC in detecting parotid masses was 95%. False-negative diagnosis was found in mucoepidermoid carcinoma, acinic cell carcinoma, and epithelial-myoepithelial carcinoma whereas there was false-positive diagnosis in cases of pleomorphic adenoma and normal parotid gland tissue.

Conclusion

FNAC is a reliable minimally invasive diagnostic method with a high sensitivity in diagnosis of lesions in parotid glands. The sensitivity of detection of malignant tumors in parotid glands was low due to the biopsy technique used, and depended on tumor location. Postoperative complications decreased after superficial parotidectomy.

Warthin's tumour - Resolution following FNA

This case report describes the acute presentation of a patient with a Warthin's tumour in his right parotid gland and complete resolution of the tumour following fine needle aspiration biopsy.

Imaging findings of necrotizing sialometaplasia of the parotid gland: case report and literature review

Although necrotizing sialometaplasia (NS) of the parotid gland is rare and occasionally presents as a lesion that mimics a malignant tumour, imaging findings in cases of NS have been rarely reported. We describe here a case of NS in which there was an increasing lesion manifesting overnight on the parotid gland in an 83-year-old male. We also investigated the use of pre-operative imaging based on previous reports and discuss the importance of these images in helping to guard against overzealous treatment. It is critically important to closely examine whether there are aspects of NS, such as the present case, in pre-operative MRI findings that can be useful in proper diagnosis and treatment.

[Patterns of xanthogranulomatous reaction in salivary glands. Histomorphological spectrum and differential diagnosis]

Xanthogranulomatous inflammation is an uncommon subtype of chronic inflammatory processes that has been mainly reported in the kidneys, gallbladder and other less common sites. Due to the presence of tumefactive mixed inflammatory infiltrates with variable involvement of surrounding soft tissues, this benign condition is often mistaken for a malignancy on clinical examination. In the salivary glands xanthogranulomatous inflammation is rare and mainly represents reactive changes secondary to a preexisting lesion, in particular infarcted Warthin tumors as well as ruptured ductal cysts and other sialectatic ductal changes. A special type of xanthogranulomatous salivary gland disease is represented by the rare primary (idiopathic) xanthogranulomatous sialadenitis without identifiable predisposing parenchymal or ductal lesions. The histological differential diagnosis is mainly based on the dominant histological pattern and encompasses among others inflammatory pseudotumors of various etiologies (e.g. inflammatory myofibroblastic tumor, IgG4-related disease and sarcoidosis), neoplastic and paraneoplastic xanthogranulomatosis, malignant lymphoma and carcinoma with secondary xanthogranulomatous reactions. Thus, identification of the underlying lesion is necessary for correct classification and to avoid overlooking more serious neoplastic or autoimmune diseases.

Clinical utility of fine needle aspiration cytology in pediatric parotid tumors

OBJECTIVE

The purpose of this study was to evaluate the usefulness and accuracy of fine needle aspiration cytology (FNAC) in the diagnosis of pediatric parotid tumors.

METHODS

From June 2002 to June 2012, 22 patients ≤18-years-of-age with parotid mass were treated at Chonnam National University Hospital. Included in the study were 21 cases with preoperative FNAC. A retrospective chart review analyzed the results of FNAC and compared them with the corresponding histopathological diagnosis.

RESULTS

Twenty-one of the 22 patients had undergone preoperative FNAC, which diagnosed pleomorphic adenoma in 13 patients. The remaining eight patients were diagnosed with benign tumor (n = 6), malignant tumor (n = 1) or Kimura disease (n = 1). All 21 patients underwent parotid tumor removal. FNAC had a diagnostic sensitivity of 92.3%, positive-predictive value of 92.3% and accuracy of 90.5% for diagnosing pleomorphic adenoma of pediatric parotid tumor. FNAC had a diagnostic sensitivity of 100%, a positive-predictive value of 85% and accuracy of 85.7% for diagnosing benign parotid tumor.

CONCLUSIONS

Preoperative FNAC is a useful and accurate adjunct for preoperative evaluation of pediatric parotid tumors. We recommend that preoperative FNAC should be part of the initial evaluation of pediatric patients with parotid masses.

MAML2 rearrangement in Warthin's tumour: a fluorescent in situ hybridisation study of metaplastic variants

BACKGROUND

Warthin's tumour (WT) is a common benign lesion of the major salivary glands. The nature of WT remains controversial, with particular regard to the presence of clonal chromosomal abnormalities, including the t(11;19) translocation involving the CRTC1 and MAML2 genes, that have been identified in both WT and mucoepidermoid carcinoma. In this study, we focused our attention on metaplastic WT variants, and we conducted a fluorescent in situ hybridisation (FISH) analysis for the presence of MAML2 gene rearrangement.

METHODS

Dual-colour FISH analysis was performed on paraffin-embedded sections of eight WTs showing metaplastic changes (five with squamous metaplasia, two with mucinous metaplasia and one with both) using a MAML2 break-apart probe.

RESULTS

Presence of split signals indicative of gene rearrangement was identified in a subset of cells in areas of squamous metaplasia in two samples of WT. No rearrangement was observed in the oncocytic epithelium, in lymphocytes and in areas of mucinous metaplasia.

CONCLUSIONS

The presence of a small subpopulation of cells carrying MAML2 rearrangement in areas of squamous metaplasia within WT could predispose these lesions to malignant transformation in mucoepidermoid carcinoma and could represent a molecular link between the two entities.

Keratocystoma of the parotid gland: a clinicopathological study and literature review

The authors investigated the clinicopathological characteristics of keratocystoma of the parotid gland. Two cases of parotid gland keratocystoma in the files of Nanjing Stomatological Hospital were analysed. These slowly growing parotid gland tumours occurred in two women aged 29 and 49 years. The cut surface showed multilocular cystic lesions filled with keratin materials. Histologically, there were multi-cystic spaces and solid epithelium islands, containing keratinized lamellae. Without cytological atypia, the lining stratified squamous epithelium showed apparent keratinization through an orthokeratotic or parakeratotic pathway. No skin appendage formation was observed. Both cases immunoreactively stained positively for AE1/AE3 and CK5/6 but negatively for CK8/18, S-100 and Calponin. There was no evidence of recurrence 3 or 4 years after superficial parotidectomy. The data from these two cases and cases previously published suggest that keratocystoma of the parotid gland is a benign cystic neoplasm. Surgical resection is apparently sufficient for cure.

Diagnostic accuracy of fine-needle aspiration cytology in Warthin tumors

BACKGROUND

Our aim was to evaluate the diagnostic accuracy of fine-needle aspiration cytology (FNAC) for Warthin tumors of the parotid gland.

METHODS

All cytologic diagnoses of Warthin tumor between 1990 and 2007 were correlated with available histology. In addition, our results were compared to current literature.

RESULTS

In 310 cases, Warthin tumor was diagnosed by FNAC. In 133 cases, (43%) both cytology and histology were available. In 127 of these 133 cases (95.5%), the diagnosis Warthin tumor was confirmed by histology. In 4 cases (3%), a benign lesion was diagnosed and 2 (1.5%) revealed a malignant lesion. On review, those cytologic diagnoses were not certain. In the literature, 11 missed malignancies (5.4%) in 202 cases were reported.

CONCLUSION

The diagnostic accuracy of FNAC for the diagnosis of Warthin tumor is high and the percentage of missed malignant tumors is very low. Our results imply that a cytologic diagnosis of Warthin tumor may justify conservative treatment.

Diagnosing common parotid tumours with magnetic resonance imaging including diffusion-weighted imaging vs fine-needle aspiration cytology: a comparative study

OBJECTIVES

the purpose of this study was to evaluate the accuracy of MRI combined with diffusion-weighted imaging (DWI) vs fine-needle aspiration cytology (FNAC) in diagnosing common parotid masses.

METHODS

25 consecutive patients (mean age 61 years) with parotid masses were included in this study. Informed consent and ethical approval was obtained. 22 patients underwent both MRI combined with DWI and FNAC. From DWI data, apparent diffusion coefficient maps were generated. The MRI study protocol consisted of T(1) weighted spin echo; T(2) weighted and T(2) weighted fat-suppressed turbo spin echo; DWI; and T(1) weighted fat-suppressed post-contrast images. MRI and FNAC diagnoses were compared with histopathology. Youden's index was used to compare the two methods.

RESULTS

masses comprised eight Warthin tumours, eight adenomas (six pleomorphic adenomas, two basal cell adenomas), five carcinomas, two lipomas, one haemagioma and one benign lymphadenopathy. Technically, MRI was successful in 24 of the 25 patients (96%), FNAC was successful in 20 of the 23 patients (87.0%). The accuracy, sensitivity and specificity of MRI without DWI were 96%, 80% and 100%, respectively. Diagnostic accuracy did not increase by adding DWI to conventional MRI; however, DWI was helpful for diagnosing benign tumour histology. MRI combined with DWI was successful for determining accurate tumour typing in all benign masses except one lymphadenopathy. When FNAC had adequate material the accuracy, sensitivity and specificity were 95%, 75% and 100%, respectively. Youden's index was 0.80 for MRI and 0.75 for FNAC.

CONCLUSIONS

MRI combined with DWI seems to have similar diagnostic potential as FNAC in differentiation of benign vs malignant parotid masses.

Induction of Parotitis by Fine-Needle Aspiration in Parotid Warthin's Tumor

OBJECTIVES: To estimate parotitis caused by fine-needle aspiration (FNA) in parotid Warthin tumor.

STUDY DESIGN: Case series with chart review.

SETTING: Hospital records were reviewed for 104 parotid tumors (103 patients) including 35 Warthin tumors, which underwent FNA within our department.

RESULTS: Three patients with four Warthin tumors among them noticed parotid pain, swelling, and abscess formation as a consequence of acute parotitis after FNA. Examinations of the materials obtained from tumor puncture or drainage before the start of antibiotic therapy showed no bacterial association in any patient. Two of the patients with Warthin tumor underwent parotidectomy, and the surgical specimens indicated histopathological changes with necrosis, abscess, granuloma, and the infiltration of inflammatory cells including Langhans-type multinucleated giant cells.

CONCLUSIONS: It is conceivable that Warthin tumor bears the characteristics of inflammation induced by the FNA procedure without any relation to infection. Therefore, it may be better to avoid routine FNA and give priority to diagnostic imagings over FNA in the diagnosis of tumors strongly suspected as Warthin tumor.

Tumor-to-tumor metastasis: Warthin tumor as a recipient of lung carcinoma and of renal carcinoma - Report of two cases

Tumor-to-tumor metastasis is an exceedingly rare event with only about 100 cases reported in the English written literature. We report two cases of a 65-year-old man with duplicity of colonic and lung adenocarcinomas who presented with swelling of the left parotid gland, and of a 75-year-old man who presented with swelling of the right parotid gland. Microscopical and immunohistochemical examination showed metastasis of lung carcinoma and of renal carcinoma, respectively, to Warthin tumor as the first clinical manifestation of the malignancy in the latter case. To the best of our knowledge, such a phenomenon has not been reported so far.

A closer look at Warthin tumors and the t(11;19)

The translocation t(11;19)(q21;p13) has been described in mucoepidermoid carcinoma (MEC) and rarely in Warthin tumors (WT), both tumors of the salivary gland. The translocation creates a fusion gene in which exon 1 of CRTC1 is linked to exons 2-5 of MAML2. To verify the translocation in WT, we performed nested reverse transcriptase-polymerase chain reaction using RNA from 48 WTs. This revealed the t(11;19)(q21;p13) translocation and expression of the chimeric gene in two metaplastic WT samples, but in none of the remaining ordinary 46 WTs. On review, the two positive cases were classified as tumors highly suspect for MEC. Indeed, our experience and published observations of the t(11;19)(q21;p13) translocation in WT reveal that only a small subset of WTs are positive, and that these tumors are often classified as infarcted or metaplastic WT, known to overlap considerably with MEC on purely morphological grounds. We therefore conclude that the presence of the t(11;19)(q21;p13) rearrangement favors a diagnosis of MEC.

Acute parotitis as a complication of fine-needle aspiration in Warthin's tumor. A unique finding of a 3-year experience with parotid tumor aspiration

OBJECTIVE/HYPOTHESIS

Fine needle aspiration (FNA) is an accurate, cost-effective tool for the study of salivary gland lesions. Although complications are extremely rare, salivary gland FNA can lead to hemorrhage, facial nerve injury, and cellulitis at the needle puncture site. Some studies suggest that FNA can cause infarction or metaplastic transformation of benign Warthin's tumors. We review our recent experience with FNA of the parotid gland, focusing on possible complications and pitfalls.

STUDY DESIGN AND SETTING

The medical records of all patients who underwent FNA of the parotid gland from 2000 to 2002 in the Department of Otolaryngology-Head and Neck Surgery of a major tertiary-care referral center were reviewed. Cytological results were compared to the histological diagnosis and complications were recorded.

RESULTS

Of the 256 lesions aspirated, 99 patients (39%), were cytologically diagnosed as benign tumors, including 31 (12%) Warthin's tumors, of which 16/17 resected and confirmed histologically. Five patients with Warthin's tumor had post-FNA parotitis and were treated accordingly.

CONCLUSIONS

The combination of cystic spaces surrounded by oncocytic cells and a poor blood supply makes the tumor susceptible to infarction and inflammation. Our findings indicate that FNA is a strong and reliable tool in the investigation of the salivary glands. Nevertheless, when Warthin's tumor is clinically suspected on the basis of its location (tail of the parotid gland), cystic texture, patient sex (male) and age, one should consider parotitis as a possible complication.

EBM RATING

C-4.

Preoperative cytology in the management of parotid neoplasms

BACKGROUND

This study evaluates the diagnostic role of preoperative cytology of parotid neoplasms. The method is particularly useful in the evaluation of the parotid diseases in which the same clinical features may be treated variously. Fine-needle aspiration biopsy is a simple and well-tolerated diagnostic tool, which provides accurate information for diagnosis and follow-up of the disease. The accuracy of the method partly depends on the operator skill.

MATERIALS AND METHODS

From a series of 452 subjects who underwent parotidectomy, preoperative cytological evaluation was available in 310 and compared with histological diagnosis in a retrospective review.

RESULTS

The agreement between histotype determination using fine-needle aspiration biopsy and final histological diagnosis was 79%, specificity was 100%, sensitivity was 83%, and diagnostic accuracy was 97%.

CONCLUSION

These findings demonstrated that, given the low complication rate, preoperative cytology is particularly useful in diagnosing parotid disease and in planning the surgical strategy and approach.

Kann die präoperative Feinnadelpunktion bei Parotistumoren die definitive histologische Diagnose erschweren?

INTRODUCTION

Fine-needle aspiration cytology (FNAC) is a minimally invasive procedure that offers high specifity and acceptable sensitivity in the preoperative diagnosis of parotid tumors. FNAC provides information that can be particularly valuable in surgical planning and patient education. In some cases, it may even help prevent unnecessary surgery. After an FNA procedure, on rare occasions, morphological changes in the tumor may be observed and can make a definitive histological examination difficult or even impossible.

METHODS

Histopathological changes in parotid tumors after preoperative FNAC are described on the basis of a case report and a survey of the literature.

RESULTS

In rare cases, puncture-induced histopathological changes, such as hyalinization of the subepithelial stroma, necrosis and squamous metaplasia, so extensive that a definitive histological diagnosis is difficult, are observed. In the present case report, fine-needle aspiration of a 3 x 2 cm tumor, which had been classified as malignant on the basis of cytological findings, resulted in complete necrosis and made a definitive histological diagnosis impossible. Similar cases have been described by other authors in recent years.

DISCUSSION

In rare cases, histological changes in the tumor tissue can occur after an FNA procedure, making a definitive histological examination difficult or even impossible. When a preoperative FNAC is performed, the pathologist in charge should be advised accordingly. In addition, patients should be informed about this infrequent risk before undergoing the procedure.

Massive squamous metaplasia of the thyroid gland – Report of three cases

Three cases of massive squamous cell metaplasia in Hashimoto's thyroiditis are reported. The patients were two men and one woman aged 24, 52, and 55 years, respectively. In all three patients, the glandular parenchyma was replaced by hypocellular fibrous tissue with scattered chronic inflammatory infiltrate. Follicular cells were almost absent; the majority of residual epithelial cells formed squamous nests that were partly solid and partly cystic. There were three types of epithelial cells - squamous, basaloid, and follicular, with oncocytic differentiation. The squamous and basaloid cells showed strong positivity high molecular weight (HMW) cytokeratin, moderate to strong expression of galectin-3 (2/3), and nuclear expression of p63 protein (2/3). The staining pattern of p63 was identical to that of HMW, with predominant positivity at the periphery of cell nests. In one case, weak but unequivocal positivity of thyroid transcription factor-1 also was present. We believe that metaplasia was caused by Hashimoto's thyroiditis. The cases presented here are extremely rare, and only two convincing similar cases have been reported in the English literature so far. They may represent a diagnostic pitfall and should not be misdiagnosed as a malignancy, in particular as squamous cell or mucoepidermoid carcinoma.

Warthin's tumor with multiple granulomas: A clinicopathologic study of six cases

Granulomatous inflammation occurring in Warthin's tumor is a rare phenomenon. It has been suggested that prior fine-needle aspiration (FNA) might be a triggering factor. We studied cases of Warthin's tumor with granulomatous inflammation to analyze the possible relationship with prior FNA. Granulomatous inflammation was noted in 6 cases (1.6%) of 382 cases of Warthin's tumor in a medical center. Clinical history, histology, and cytology slides were reviewed. Special stains for detection of infective agents were performed. All 6 cases showed typical features of Warthin's tumor accompanied by multiple granulomas. No specific microbiologic infective agents were revealed in these cases. There were 2 cases with history of preoperative FNA; both already had granulomas in Warthin's tumor in cytologic specimens taken by aspiration. The pathogenesis of granulomatous inflammation in Warthin's tumor remains speculative. Our observation of granulomas in the cytology specimens did not support the hypothesis of prior FNA being the cause.

Fine-needle Aspiration Cytology in the Management of Salivary Gland Tumors: An Australian Experience

We conducted a retrospective study of 104 cases of salivary gland tumors that were initially assessed by fine-needle aspiration biopsy (FNAB). Based on subsequent histopathologic analysis of excised specimens, we found that preoperative FNAB was highly sensitive and specific for both benign and malignant tumors—including the most common, pleomorphic adenomas and squamous cell carcinomas, respectively. Despite its possible drawbacks, we conclude that preoperative FNAB is a useful tool in the management of salivary gland tumors.

Oncocytic mucoepidermoid carcinoma of parotid gland origin

This article reports 3 cases of oncocytic mucoepidermoid carcinoma of the parotid gland and compares them with 9 cases from the literature with emphasis on clinical behavior, treatment, and recurrence rate. The tumor occurs most often in the middle-aged to elderly, with a decided predilection for the parotid gland. All three oncocytic mucoepidermoid carcinomas from the Armed Forces Institute of Pathology series were low grade with extensive oncocytic change. Treatment modalities consisted of superficial parotidectomy, total parotidectomy, or total parotidectomy. The mean follow-up interval was 5.5 years. Only one case from the literature, a high-grade mucoepidermoid carcinoma, recurred. Results of this study indicate that the parotid gland oncocytic mucoepidermoid carcinoma behaves in a fashion similar to typical mucoepidermoid carcinoma, with prognosis dependent on clinical stage, histopathologic grade, and adequacy of treatment. Recognizing the spectrum of oncocytic differentiation in salivary gland tumors will serve to establish appropriate diagnoses and treatment.

Diagnostic accuracy and pitfalls in fine-needle aspiration interpretation of Warthin tumor

BACKGROUND

Despite its well-defined histologic appearance, the often variegated cytomorphologic appearance of Warthin tumor (WT) on fine-needle aspiration (FNA) may lead to an erroneous cytopathologic interpretation. In this study, the authors analyzed the potential sources of diagnostic errors and overall accuracy of FNA diagnosis of WT.

METHODS

A retrospective search of The Johns Hopkins Hospital Surgical Pathology files (1985-2001) revealed 97 patients with WT, including 31 patients who underwent prior FNA. A comprehensive review of cytopathologic material was undertaken to calculate the overall accuracy of FNA and to identify sources of diagnostic error.

RESULTS

All tumors presented in the parotid gland. Four tumors (13%) were deemed inadequate for interpretation due to insufficient material. The FNA diagnosis of WT was rendered in only 20 tumors (74%). The remaining 7 tumors (26%) were misdiagnosed on FNA as consistent with or suspicious for carcinoma or some other neoplastic process. A retrospective review of the tumors, which were over-called on FNA, showed a predominance of necrotic or cellular debris (n = 6 tumors; 22%), significant epithelial metaplasia with atypia (n = 4 tumors; 15%), background inflammation suspicious for tumor diathesis (n = 3 tumors; 11%), spindle cells (n = 1 tumor; 4%), and abundant mucin with keratinized squamous cells (n = 1 tumor; 4%).

CONCLUSIONS

FNA is moderately accurate for diagnosing WT, with a 74% accuracy rate in the current series. Cytologic misinterpretation may occur due to a lack of characteristic cytomorphologic features of WT and overabundance of one or more of the following: squamous metaplasia/atypia, mucoid/mucinous background, spindle-shaped cells, and cystic/inflammatory debris. An adequate awareness of these potential sources of erroneous diagnoses, coupled with appropriate clinical findings, may result in a higher accuracy rate.